Enkephalin is a natural opiate receptor aganist and is believed to be a mixture of two pentapeptides: H-Tyr-Gly-Gly-Phe-Met-OH (methionine-enkephalin), and H-Tyr-Gly-Gly-Phe-Leu-OH (leucine-enkephalin). Hereinafter, the name enkephalin is used generically to embrace all such compounds.
It has been reported by Beluzzi et.al., Nature, 260, 625 (1976), that when enkephalin is injected into the brain ventricle of rats, a profound analgesia is obtained. It is also known in the art that enkephalin is acted upon by a group of enzymes known generically as enkephalinases, which are also naturally occurring and is inactivated thereby. The present invention provides a method for inhibiting the action of enkephalinases, and compounds useful for accomplishing said method.
European Patent Application No. 79105015.6, publication No. 12401 discloses certain dipeptide derivatives which are described as possessing antihypertensive effects.